1. Field of the Invention
The present invention relates to electronic modules that include a substrate, a built-in electronic component that is built into the inside of the substrate and a surface mount electronic component that is mounted on a front surface of the substrate.
2. Description of the Related Art
To date, electronic modules that include electronic components provided inside and on a front surface of a substrate of the electronic module have been widely used as high-functionality electronic modules.
An example of such an electronic module is disclosed in Japanese Unexamined Patent Application Publication No. 2010-136143. An electronic module 400 of the related art disclosed in Japanese Unexamined Patent Application Publication No. 2010-136143 is illustrated in FIG. 5.
The electronic module 400 includes a substrate 101.
Electronic components 102, 103 and 104 are mounted on a front surface of the substrate 101.
A protective layer 105 composed of a resin is formed on the front surface of the substrate 101 on which the electronic components 102 to 104 are mounted. The front surface of the protective layer 105 is formed so as to be flat so as to be capable of being sucked by the nozzle of a vacuum suction apparatus.
In the electronic module 400, a single-layer substrate is used as the substrate 101, but a multilayer substrate may be used instead. In addition, another electronic component may be built into the inside of the substrate, thereby achieving an increase in the functionality of the electronic module.
A reduction in the size of electronic and electrical devices, as well as a reduction in the size of electronic modules used in such devices is desired. In such size reduction, it is important that the planar area seen in a direction perpendicular to the plane of the device or module be decreased and also that the profile be reduced.
However, in the above-described electronic module 400 of the related art, since the protective layer 105 is formed on the front surface of the substrate 101 on which the electronic components 102 to 104 are mounted, there is a problem in that the profile may not be sufficiently low. As well as protecting the electronic components 102 to 104, the protective layer 105 serves as a layer that can be sucked by the nozzle of a vacuum suction apparatus when the electronic module 400 is to be mounted on the substrate of an electronic or electrical device.
In addition, in the above-described electronic module 400 of the related art, since the electronic components 102 to 104 having different heights and planar areas are built into the inside of the protective layer 105, unevenness may occur on the front surface of the protective layer 105. As a result, when unevenness occurs on the front surface of the protective layer 105, there is a problem in that the protective layer 105 may not be able to be sucked by the nozzle of a vacuum suction apparatus.